WASHINGTON — Senator Feinstein, the oldest member of Congress, fell in her home and went to a hospital for a short time, her office said on Wednesday.

The 90-year-old Coast Democrat, who has faced mounting concerns about her health and her ability to perform the duties of a senator, “briefly went to the hospital yesterday afternoon as a precaution after a minor fall in her home,” her office said in a statement.

All of her scans were clear, and she returned home later Tuesday, said her spokesman Adam Russell, who provided no further details.

The Senate majority leader, Charles “Chuck” Schumer, said in a statement he spoke with Ms. Feinstein on Wednesday morning.

“She said she suffered no injuries and briefly went to the hospital as a precaution,” Mr. Schumer said. “I’m glad she is back home now and is doing well.”

The San Francisco hospital visit comes after Ms. Feinstein missed months of work in Washington earlier this year when she was hospitalized for the shingles virus and its side effects. 

Since her return to work in May, she has traveled the Capitol halls in a wheelchair and has often appeared confused and disoriented.

Ms. Feinstein has defended her ability to perform her job, though her office said in May that she was still experiencing vision and balance impairments from the shingles virus.

Ms. Feinstein, who took office in 1992, announced earlier this year that she would not seek reelection in 2024. Several Democrats have already entered the race to replace her.

During her hospitalization in the spring, some liberal House Democrats publicly called on her to resign, saying her absence had grounded the push to confirm President Biden’s judicial nominees. However, leading Democrats, including Messrs. Biden and Schumer, publicly stood beside her.

Nonetheless, Ms. Feinstein’s retirement plans have sparked a competitive Democratic contest to replace her, led by a trio of House lawmakers, Representatives Barbara Lee, Katie Porter, and Adam Schiff.

If Ms. Feinstein resigns before the 2024 election, Governor Newsom would name her replacement, potentially reordering the race to succeed her. 

The governor said in 2021 that he would nominate a Black woman to fill the seat if Ms. Feinstein were to step aside.

Ms. Lee is Black, and becoming the incumbent could be a decisive advantage in the contest, but it’s unknown if Mr. Newsom would consider Ms. Lee, given that she is already running for the seat. Ms. Porter and Mr. Schiff are white.

Ms. Feinstein has had a storied political career that broke gender barriers as she rose to leadership posts in the U.S. Senate from San Francisco’s City Hall. 

She played key roles in political battles over issues including reproductive rights and environmental protection, gaining a reputation as a pragmatic centrist.

In recent years, however, she has taken a step back from senior roles at the Capitol. She relinquished the top Democratic spot on the Judiciary Committee in 2020 amid criticism from liberals on how she handled the confirmation of Justice Amy Coney Barrett. 

Earlier this year, she declined to serve as the Senate president pro tempore, the most senior member of the majority party who daily opens the Senate chamber, even though she was in line to do so.

Ms. Feinstein had also requested to be replaced on the Senate Judiciary panel during her 10-week hospital stay earlier this year, but Republicans declined to allow the replacement. Even after she returned, concerns continued that she would not be able to make it for every crucial vote.

The Senate is expected to resume work in Washington in early September.